There is a previously known moving coil type actuator having a structure in which an armature is opposite to a field permanent magnet through a magnetic gap (For example, see Patent Reference 1).
Patent Reference 1: JP-A-2000-308328
The invention disclosed in Patent Reference 1 relates to a moving coil type linear actuator filed by the same inventors as those of this application. The invention is accomplished for facilitating connection processing of a connecting wire and a neutral point of an armature coil and for providing a linear motor capable of increasing the thrust per a unit volume of a core block.
The linear motor is provided with an armature opposite to a field permanent magnet through a magnetic gap. The armature has an armature core divided into a plurality of core blocks in a thrust direction and an armature coil. The armature coil wound around each core block is taken out by unlacing the winding ending portion of a coil conductor onto the winging starting portion by ½ turn so that they are arranged oppositely on both sides of the core block. A wiring substrate having a wiring pattern for connecting the connecting wire and neutral point of the armature coil is provided on both sides of a yoke of the armature core.
Such a configuration could facilitate the connection processing of the connecting wire and neutral point of the armature coil and increase the thrust per unit volume of the core block.
However, power could not be easily supplied to the armature which moves. In order to obviate such an inconvenience, the linear actuator of not a moving coil type but a moving magnet type is developed.
FIG. 3 is a view showing a moving magnet type linear actuator which is a prior art of this invention; (a) is a plan view and (b) is a sectional side view.
In FIG. 3, reference numeral 60 generally denotes a moving magnet type linear actuator which mainly includes a movable body 20, a stator 30, a linear guide 40 and a position detecting portion 50.
The movable body 20 is mainly constructed of a field permanent magnet 21 and a magnetic yoke 23 which holds it. The stator 30 is mainly constructed of a stator base 31 and an armature 32 fixed thereon. The armature 32 includes a magnetic iron core 33, an armature winding 34 wound around the core, an insulating layer 35 encircling the armature winding 34 and a power supplying wire 36 which serves to supply power to the armature winding 34.
The linear guide 40 (FIG. 3(b)) is mainly constructed of linear guide rails 41, liner guide blocks 42 running thereon, and stopper mechanisms 43 (FIG. 3(a)) for forcibly stopping the running of the linear guide block 42 at both ends in the running direction of the linear actuator 60.
The position detecting portion 50 is mainly constructed of a detecting portion supporter 51 fixed on the stator base 31, a linear scale detecting portion 52 fixed on the detecting supporter 51 and a linear scale 53 fixed on the side of the movable body adjacently apart from the linear scale detecting portion 52, and a signal line 54.
As understood from the above description, the magnetic yoke 23 is provided behind the field permanent magnet 21, and both constitute the moving body serving as a magnetic circuit.
The armature 32 has the magnetic iron core, and the armature winding 34 is wound on the slots made at an equal pitch in the magnetic iron core. When a current is passed through the armature winding 34, the linear actuator 60 moves within a stroke which a difference between the lengths of the armature and field movable body.